#!/bin/sh

if ! which gnuplot > /dev/null 2>&1
then
    echo "gnuplot not found - skipping graph creation" >&2
    exit 1
fi

gnuplot<<EOF
    set terminal postscript eps color enhanced "Helvetica,20"
    set output '../numberDensity.eps'
    set decimalsign '.'

    set format xy '%g'
    set xtics 1e2 mirror
    set xlabel 'v(m^{3})'
    set ytics 1e5 mirror
    set ylabel 'n(m^{-3}m^{-3})'

    set logscale xy
    set xrange [1e-5:1e2]
    set yrange [1e-15:100]
    set key at graph 0.55,0.5

    C = 1
    N0 = 2.5
    v0 = 0.01

    # Dimensionless volume
    X(x) = x/v0

    # Initial condition
    n0(x) = (N0/v0)*X(x)*exp(-X(x))

    T(t) = C*N0*t

    # For solution of quadratic saddle point equation
    p(x) = -1/X(x)
    q(t) = -(T(t)/(T(t) + 2))

    # Saddle point calculation
    y_s(t,x) = -p(x)/2 + sqrt((p(x)/2)**2 - q(T(t)))

    # Dimensionless spectrum function
    phi(x,t) = (8*exp((y_s(t,x) - 1)*X(x)*2))/(((T(t) + 2)**2)*y_s(t,x)*(4*pi*(2 - 1/(y_s(t,x)*X(x)))))

    # Number density at time t
    n(x,t) = (N0/v0)*phi(x,t)

    numberDensity = '../postProcessing/numberDensity/10/numberDensity.xy'

    plot n0(x) ls -1 t 'Initial Condition',\
    n(x,10.0) dt 2 lc rgb 'black' t 'Scott (1968)',\
    numberDensity every ::0::46 u 1:2 w p pt 1 lc rgb 'black' t 'air1',\
    numberDensity every ::47::55 u 1:2 w p pt 5 lc rgb 'black' t 'air2',\
    numberDensity every ::56::70 u 1:2 w p pt 9 lc rgb 'black' t 'air3'
EOF

#------------------------------------------------------------------------------
